Method of rolling tubes from hollow blocks



July 29,1930. M. ROECKNER METHOD ROLLING TUBES FROM HOLLOW BLOCKS FiledFeb. 6, 1928 a j fnrentvr: v/(m M LKL 1 E LLLL Patented July 29. 1930UNITED STATES MARTIN ROECKNEB, F MULHEIM-R' U HR,

PATENT OFFICE NIGTE STAH LWERKE AKTIENGESELLSCHAFT, 0F DUSSELDORF,GERMANY METHOD OF ROLIING TUBES FROM HOLLOW BLOCKS Application filedFebruary 6, 1928, Serial No.

It is known, for instance by my prior U. S. Patent 1,610,593,'to maketubes from a hollow block by subjecting the latter to the action of asystem of pairs of rolls arranged about the hollow block at a certaindistance from its axis, each pair of rolls acting with one roll frominside and With the other roll from outside said block upon the walls ofthe latter. The pairs of rolls are of gradually increasing width and ofadjustable working depth so that from the first pair of rolls acircumferential nick beginning adjacent the front end of the block iscut into the material of the hollow block, which nick is graduallynvidened by the following pairs of rolls to-' Ward said end; the axes ofsaid rolls being inclined to the axis of the hollow block.

Said method has the drawback that slight corrugations and unevenesses inthe wall of 29 the tube produced, which sometimes occur by of saidslight action of the working part of the rolls thereon, could hithertonot be removed by a working process'directly adjoining the rollingprocess. It was necessary, for a removal corrugations and unevenesses,to use a separate machine, for instance one a used for rounding andstraightening welded tubes.

The present invention provides improved \30 means for overcoming thisdrawback and pertion, the rolls are widened and, that the how theinvention can be put into practice.

Figs. 1 and 2 illustrate the improved arrangement for practice.

The reference letters designate: A the main deforming part of the rolls,B the hollow 252,376, and in Germany February 25, 1927.

block to be rolled, C the outlet extension widening the rolled tube, andD that part imparting a pressure to the tube without deforming the same.

What I claim, is: In a method of rolling tubes from hollow blocksconsisting in drawing out the latter. in

substantiallyaxial direction by the utilization of palrs of rolls actingboth from inside and outside upon said block and of which the axes areinclined tothe axis of the latter, widening the tube by the same pairsof rolls directly after its formation from the hollow block andsubsequently imparting thereto a pressure .without deforming it byoutlet extensions of said rolls.

In testimony whereof I have hereunto set my hand. MARTIN ROECKNER.

putting the invention into GERMANY, ASSIGNOR TO THE FTRM OF VEREI-

